On Tue, Jul 16, 2019 at 11:00:55PM +0800, Dong Aisheng wrote:
> There's a few limitations on the original one cell clock binding
> (#clock-cells = <1>) that we have to define some SW clock IDs for device
> tree to reference. This may cause troubles if we want to use common
> clock IDs for multi platforms support when the clock of those platforms
> are mostly the same.
> e.g. Current clock IDs name are defined with SS prefix.
>
> However the device may reside in different SS across CPUs, that means the
> SS prefix may not valid anymore for a new SoC. Furthermore, the device
> availability of those clocks may also vary a bit.
>
> For such situation, we want to eliminate the using of SW Clock IDs and
> change to use a more close to HW one instead.
> For SCU clocks usage, only two params required: Resource id + Clock Type.
If this is how SCU firmware addresses the clock, I agree that it's worth
witching to this new bindings, which describes the hardware (SCU
firmware in this case) better, IMO.
> Both parameters are platform independent. So we could use two cells binding
> to pass those parameters,
>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
> Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
> Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx>
> Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> ---
> ChangeLog:
> v2->v3:
> * Changed to two cells binding and register all clocks in driver
> instead of parse from device tree.
> v1->v2:
> * changed to one cell binding inspired by arm,scpi.txt
> Documentation/devicetree/bindings/arm/arm,scpi.txt
> Resource ID is encoded in 'reg' property.
> Clock type is encoded in generic clock-indices property.
> Then we don't have to search all the DT nodes to fetch
> those two value to construct clocks which is relatively
> low efficiency.
> * Add required power-domain property as well.
> ---
> .../devicetree/bindings/arm/freescale/fsl,scu.txt | 12 +++++++-----
> include/dt-bindings/firmware/imx/rsrc.h | 17 +++++++++++++++++
> 2 files changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> index 5d7dbab..351d335 100644
> --- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> @@ -89,7 +89,10 @@ Required properties:
> "fsl,imx8qm-clock"
> "fsl,imx8qxp-clock"
> followed by "fsl,scu-clk"
> -- #clock-cells: Should be 1. Contains the Clock ID value.
> +- #clock-cells: Should be either
> + 2: Contains the Resource and Clock ID value.
> + or
> + 1: Contains the Clock ID value. (DEPRECATED)
> - clocks: List of clock specifiers, must contain an entry for
> each required entry in clock-names
> - clock-names: Should include entries "xtal_32KHz", "xtal_24MHz"
> @@ -162,7 +165,7 @@ firmware {
>
> clk: clk {
> compatible = "fsl,imx8qxp-clk", "fsl,scu-clk";
> - #clock-cells = <1>;
> + #clock-cells = <2>;
> };
>
> iomuxc {
> @@ -192,8 +195,7 @@ serial@5a060000 {
> ...
> pinctrl-names = "default";
> pinctrl-0 = <&pinctrl_lpuart0>;
> - clocks = <&clk IMX8QXP_UART0_CLK>,
> - <&clk IMX8QXP_UART0_IPG_CLK>;
> - clock-names = "per", "ipg";
> + clocks = <&uart0_clk IMX_SC_R_UART_0 IMX_SC_PM_CLK_PER>;
> + clock-names = "ipg";
> power-domains = <&pd IMX_SC_R_UART_0>;
> };
> diff --git a/include/dt-bindings/firmware/imx/rsrc.h b/include/dt-bindings/firmware/imx/rsrc.h
> index 4e61f64..fbeaca7 100644
> --- a/include/dt-bindings/firmware/imx/rsrc.h
> +++ b/include/dt-bindings/firmware/imx/rsrc.h
> @@ -547,4 +547,21 @@
> #define IMX_SC_R_ATTESTATION 545
> #define IMX_SC_R_LAST 546
>
> +/*
> + * Defines for SC PM CLK
> + */
> +#define IMX_SC_PM_CLK_SLV_BUS 0 /* Slave bus clock */
> +#define IMX_SC_PM_CLK_MST_BUS 1 /* Master bus clock */
> +#define IMX_SC_PM_CLK_PER 2 /* Peripheral clock */
> +#define IMX_SC_PM_CLK_PHY 3 /* Phy clock */
> +#define IMX_SC_PM_CLK_MISC 4 /* Misc clock */
> +#define IMX_SC_PM_CLK_MISC0 0 /* Misc 0 clock */
> +#define IMX_SC_PM_CLK_MISC1 1 /* Misc 1 clock */
> +#define IMX_SC_PM_CLK_MISC2 2 /* Misc 2 clock */
> +#define IMX_SC_PM_CLK_MISC3 3 /* Misc 3 clock */
> +#define IMX_SC_PM_CLK_MISC4 4 /* Misc 4 clock */
> +#define IMX_SC_PM_CLK_CPU 2 /* CPU clock */
> +#define IMX_SC_PM_CLK_PLL 4 /* PLL */
> +#define IMX_SC_PM_CLK_BYPASS 4 /* Bypass clock */
It seems that there are several sets of clock type which apply to
different resources/devices? If so, can you separate them a bit with
some comments to make the list easier for readers?
Shawn
> +
> #endif /* __DT_BINDINGS_RSCRC_IMX_H */
> --
> 2.7.4
>
